In the past, numerous devices have been used for producing a simulated smoke. One such device discussed in U.S. Pat. No. 4,326,119 simulates smoke by heating a vaporizable, smoke producing liquid within a tubular coil to a predetermined temperature so as to completely vaporize the liquid. A direct current voltage source supplies the current for heating the tubular coil. Once the liquid is heated, it is released into the atmosphere as a vapor by a smoke discharge cap. Although intended to be reused, a number of components such as a heat fusible release disk and heat fusible actuator rod must be replaced. The task of maintaining an adequate supply of these components is one of the primary disadvantages of this device.
Insect foggers, although intended for an entirely different purpose, have the inherent ability to generate a toxic smoke for killing insects. For instance, in U.S. Pat. No. 3,986,670, there is disclosed an insect fogger which utilizes an aerosol container containing an insecticide solution. A plunger actuates the valve means on the aerosol container so that the contents are supplied to a coiled conduit. The insecticide solution is heated as it passes through the coiled conduit to the discharge outlet where it issues as a toxic fog. When the contents of the container are expended, the container is disposed of and replaced with a new, charged container.
Although avoiding the problem of replacing components, the insect fogger creates new equally perplexing problems. There is mounting scientific evidence tending to prove that the aerosols used to expell the contents of the container are a significant factor contributing to the depletion of the ozone layer of the earth's atmosphere. Thus, there is a need for a safer method of producing a simulated smoke without need for replacement of essential components.